This paper is two parts. The first is a listing of ten different phylum. It also describes how many of each of the phyla exist and had once existed but are now extinct. The second part discusses ten different parasitic organisms and how they have adapted to better survive and live off of their host organism.
Phyla and Parasites
Ten Phyla:
Phylum Mollusca ~ Living Species Number: World: at least 50,000; United States:
Approximately 20,000; Texas: More than 2,000; Number of Fossil Forms: 150,000
Phylum Brachiopoda ~ Living Species Number: World: 400; United States: 80; Texas: 10;
Number of Fossil Forms: 5,000
Phylum Echinodermata ~ Living Species Number: World: 7,000; United States: Approximately
2,000; Texas: Approximately 200; Number of Fossil Forms: 13,000
Phylum Chordata ~ Living Species Number: World: More than 60,000; United States: 20,000
Texas: Approximately 2,000; Number of Fossil Forms: 114,000
Phylum Conulariida ~ Living Species Number: World: Approximately150; United States: Less
than 50; Texas: Unknown but less than 10; Number of Fossil Forms: More than 250,000
Phylum Cnidaria ~ Living Species Number: World: More than 10,000; United States: 4,000; Texas: More than 50; Number of Fossil Forms: Approximately 25,000 species
Phylum Porifera ~ Living Species Number: World: 5,000; United States: About 1,000; Texas:
About 100; Number of Fossil Forms: 9,000
Phylum Protozoa ~ Living Species Number: World: More than 1.2 million with 86% still unclassified; United States: Estimated more than 20,000 in water alone; Texas: Unknown but estimated at more than 5,000; Number of Fossil Forms: Millions
Phylum Annelida ~ Living Species Number: World: Over 22,000; United States: Estimated to be
12,000; Texas: More than 5,000; Number of Fossil Forms: Estimated to be 10,000
Phylum Bryozoa ~ Living Species Number: World: 5,000; United States: More than 1,000;
Texas: About 100; Number of Fossil Forms: 15,000
Adaptations to Parasitism:
Tapeworms~ Adapted with a resistant outer covering so that their bodies are not damaged by the stomach acid in the animal that they are inhabiting. Also, they have no digestive tract which allows them to absorb food directly from the stomach.
Ascaris ~ Adapted with a sucker mouth and have no internal transportation. They need a host to survive. Its body is long and narrow which allows it to easily accommodate in the intestine of its host. It is also adapted to protect its skin against the chemicals of the host body. Also, the nervous system and sensory organs were simplified.
Platyhelminthes ~ They have adapted a thick body which protects them against the host body.
Their spines, suckers, and hooks developed to be attached and their organs which allow motion were removed.
Protozoa: Developed the ability to encysted which makes a thick, tough wall around itself and then enter a state of hibernation. Many of them avoid places which are inhospitable, such as where there is no oxygen.
Leech: Creates a cocoon for itself which is a protective covering. Adapted to be a hermaphrodite to help reproduction. Leech developed slow digestions and the ability to secrete hirudin which prevents blood clotting.
Nematode: Developed a pseudocoelom which has a body cavity lined with a mesoderm. This is a space for both circulation and internal organs. They move not with limbs but a hydrostatic skeleton.
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